US4370196A - Anisotropic etching of aluminum - Google Patents
Anisotropic etching of aluminum Download PDFInfo
- Publication number
- US4370196A US4370196A US06/362,043 US36204382A US4370196A US 4370196 A US4370196 A US 4370196A US 36204382 A US36204382 A US 36204382A US 4370196 A US4370196 A US 4370196A
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- US
- United States
- Prior art keywords
- percent
- aluminum
- etching
- nitrogen
- trichloromethane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F4/00—Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
- H01L21/32135—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only
- H01L21/32136—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas
Definitions
- This invention relates to the plasma etching of aluminum and its alloys. More particularly, this invention pertains to an improved etchant gas mixture for the plasma etching of aluminum.
- a second problem encountered in the plasma etching of aluminum and its alloys is that most etchant gas mixtures tend to etch a substrate more rapidly at the periphery than the center. This nonuniformity of etch results in undercutting of the aluminum at the periphery over the time period required to assure complete etching of the center.
- a further problem is the residues resulting from the plasma etching of aluminum. These residues, which may be formed from two sources, i.e. the photoresist and the etchant gas itself, are extremely tenacious and very difficult to remove by conventional procedures such as organic solvents or oxygen glow discharge.
- An etchant gas mixture for the anisotropic etching of aluminum or its alloys which comprises boron trichloride, trichloromethane and hydrogen to which may be added nitrogen and helium.
- the etchant compositions of this invention will produce an anisotropic etch of aluminum or its alloys with only three components, i.e. boron trichloride, trichloromethane and hydrogen.
- nitrogen and/or helium may also be added to the mixture.
- Trichloromethane is, of course, an additional source of chlorine. More importantly, however, its presence causes the formation of a polymer under conditions of glow discharge. The polymer forms on the sidewalls of the etched aluminum and prevents sidewise etching, i.e. undercutting, of the resist pattern. The exact nature of the polymer is not known.
- the subject etchant compositions contain helium.
- the function of helium is to stabilize the glow discharge and promote the integrity of the resist.
- the capacity of helium to so function is known to those skilled in the art.
- the subject etching compositions contain nitrogen. It is well known among those skilled in the art that a residue usually remains after plasma etching of aluminum. These residues are very tenacious and have resisted both physical and chemical means of removal. It has been found in accordance with this invention that the inclusion of an effective amount of nitrogen in the etching compositions of this invention either substantially eliminates these residues or sufficiently reduces their tenacity so that they can be removed by conventional procedures.
- nitrogen acts to increase the etch rate. Above a certain concentration, however, nitrogen acts as a simple diluent for the subject etchant mixture, i.e. increasing the nitrogen content beyond that point decreases the etch rate.
- the subject compositions contain, in percent by volume: from about 23 to about 83 percent, preferably from about 31 to about 53 percent, of boron trichloride; from about 11 to about 75 percent, preferably from about 11 to about 27 percent, of trichloromethane; from about 0.5 to about 9 percent, preferably from about 0.7 to about 2 percent, of hydrogen; from zero to about 55 percent, preferably from about 19 to about 36 percent, of nitrogen; and from zero to about 33 percent, preferably from about 15 to about 27 percent, of helium.
- the above percentages are applied to conventional apparatus such as a planar reactor described in an article by J. L. Vossen, Jr. in Pure and Applied Chemistry, Vol. 52, pp. 1759-1765 (1981).
- the upper electrode can be powered to between 1 and 3 kW and the lower electrode tuned to about 230 volts with respect to ground.
- the total gas pressure utilized is typically 140-175 mtorr and total gas flow is from 40-100 sccm. None of these parameters is particularly critical.
- the lower limit of boron trichloride and conversely, the upper limits of trichloromethane and hydrogen represent the point at which polymer formation approaches the etch rate on planar surfaces and etching ceases.
- the opposite limits represent the point where isotropic etching becomes significant.
- Increasing the nitrogen concentration substantially beyond 55 percent by volume decreases the etch rate to a value of no practical consequence.
- increasing the nitrogen and/or the helium content substantially above their upper limits raises the pressure which leads to more isotropic etching.
- a total flow substantially under 40 sccm material restricts the composition content required to achieve an anisotropic etch. There is no apparent limit to using higher flows. In general, the best results are obtained with the highest gas flow and lowest total pressure possible with the equipment available.
- a series of one millimicron thick aluminum coated silicon wafers was utilized as substrates.
- the wafers were overcoated with a finely patterned resist layer.
- the wafers were placed in groups of three into a parallel electrode etching reactor.
- the upper electrode was rf powered and the lower (substrate) electrode was tuned to produce a voltage to ground of 238 volts.
- the upper electrode power was 2.35 kW and the pressure was 150 mtorr.
- the gas flow was 60 sccm.
- Etching was carried out using a mixture of, on a volume basis, 69 percent boron trichloride, 29 percent trichloromethane and 2 percent hydrogen. Etching was carried out for six minutes.
Abstract
Description
______________________________________ Percent by Volume Mixture BCl.sub.3 CHCl.sub.3 H.sub.2 N.sub.2 He ______________________________________ A 43 18.5 1.5 37 0 B 49 21 2 0 28 C 34 15 1 30 20 ______________________________________
Claims (8)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/362,043 US4370196A (en) | 1982-03-25 | 1982-03-25 | Anisotropic etching of aluminum |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/362,043 US4370196A (en) | 1982-03-25 | 1982-03-25 | Anisotropic etching of aluminum |
Publications (1)
Publication Number | Publication Date |
---|---|
US4370196A true US4370196A (en) | 1983-01-25 |
Family
ID=23424458
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/362,043 Expired - Lifetime US4370196A (en) | 1982-03-25 | 1982-03-25 | Anisotropic etching of aluminum |
Country Status (1)
Country | Link |
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US (1) | US4370196A (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0076860A1 (en) * | 1981-04-15 | 1983-04-20 | Hitachi, Ltd. | Process for dry-etching an aluminum alloy |
US4462882A (en) * | 1983-01-03 | 1984-07-31 | Massachusetts Institute Of Technology | Selective etching of aluminum |
US4505030A (en) * | 1982-04-14 | 1985-03-19 | Commissariat A L'energie Atomique | Process for positioning an interconnection line on an electrical contact hole of an integrated circuit |
US4529860A (en) * | 1982-08-02 | 1985-07-16 | Motorola, Inc. | Plasma etching of organic materials |
US4547261A (en) * | 1984-09-28 | 1985-10-15 | Rca Corporation | Anisotropic etching of aluminum |
US4578559A (en) * | 1982-03-10 | 1986-03-25 | Tokyo Ohka Kogyo Co., Ltd. | Plasma etching method |
US5350488A (en) * | 1992-12-10 | 1994-09-27 | Applied Materials, Inc. | Process for etching high copper content aluminum films |
US5387556A (en) * | 1993-02-24 | 1995-02-07 | Applied Materials, Inc. | Etching aluminum and its alloys using HC1, C1-containing etchant and N.sub.2 |
US5578163A (en) * | 1991-10-21 | 1996-11-26 | Seiko Epson Corporation | Method of making an aluminum containing interconnect without hardening of a sidewall protection layer |
US5849641A (en) * | 1997-03-19 | 1998-12-15 | Lam Research Corporation | Methods and apparatus for etching a conductive layer to improve yield |
US5948570A (en) * | 1995-05-26 | 1999-09-07 | Lucent Technologies Inc. | Process for dry lithographic etching |
US6090717A (en) * | 1996-03-26 | 2000-07-18 | Lam Research Corporation | High density plasma etching of metallization layer using chlorine and nitrogen |
US20040152302A1 (en) * | 2003-02-01 | 2004-08-05 | Newport Fab, Llc Dba Jazz Semiconductor | Method for patterning densely packed metal segments in a semiconductor die and related structure |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5585670A (en) * | 1978-12-23 | 1980-06-27 | Fujitsu Ltd | Aluminum and aluminum alloy etching method |
JPS55134173A (en) * | 1979-04-04 | 1980-10-18 | Nippon Telegr & Teleph Corp <Ntt> | Etching method for aluminum or aluminum base alloy |
EP0023146A2 (en) * | 1979-07-23 | 1981-01-28 | Fujitsu Limited | Method of manufacturing a semiconductor device wherein first and second layers are formed |
US4256534A (en) * | 1978-07-31 | 1981-03-17 | Bell Telephone Laboratories, Incorporated | Device fabrication by plasma etching |
-
1982
- 1982-03-25 US US06/362,043 patent/US4370196A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4256534A (en) * | 1978-07-31 | 1981-03-17 | Bell Telephone Laboratories, Incorporated | Device fabrication by plasma etching |
JPS5585670A (en) * | 1978-12-23 | 1980-06-27 | Fujitsu Ltd | Aluminum and aluminum alloy etching method |
JPS55134173A (en) * | 1979-04-04 | 1980-10-18 | Nippon Telegr & Teleph Corp <Ntt> | Etching method for aluminum or aluminum base alloy |
EP0023146A2 (en) * | 1979-07-23 | 1981-01-28 | Fujitsu Limited | Method of manufacturing a semiconductor device wherein first and second layers are formed |
Non-Patent Citations (2)
Title |
---|
Abstract No. 288 from Electrochemical Society Extended Abstracts, vol. 81 (2), pp. 703-705 (1981) by Bruce et al. * |
Vossen, Pure & Applied Chemistry, vol. 52, pp. 1759-1765 (1980). * |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0076860A1 (en) * | 1981-04-15 | 1983-04-20 | Hitachi, Ltd. | Process for dry-etching an aluminum alloy |
EP0076860A4 (en) * | 1981-04-15 | 1984-03-26 | Hitachi Ltd | Process for dry-etching an aluminum alloy. |
US4578559A (en) * | 1982-03-10 | 1986-03-25 | Tokyo Ohka Kogyo Co., Ltd. | Plasma etching method |
US4505030A (en) * | 1982-04-14 | 1985-03-19 | Commissariat A L'energie Atomique | Process for positioning an interconnection line on an electrical contact hole of an integrated circuit |
US4529860A (en) * | 1982-08-02 | 1985-07-16 | Motorola, Inc. | Plasma etching of organic materials |
US4462882A (en) * | 1983-01-03 | 1984-07-31 | Massachusetts Institute Of Technology | Selective etching of aluminum |
US4547261A (en) * | 1984-09-28 | 1985-10-15 | Rca Corporation | Anisotropic etching of aluminum |
US5578163A (en) * | 1991-10-21 | 1996-11-26 | Seiko Epson Corporation | Method of making an aluminum containing interconnect without hardening of a sidewall protection layer |
US5350488A (en) * | 1992-12-10 | 1994-09-27 | Applied Materials, Inc. | Process for etching high copper content aluminum films |
US5387556A (en) * | 1993-02-24 | 1995-02-07 | Applied Materials, Inc. | Etching aluminum and its alloys using HC1, C1-containing etchant and N.sub.2 |
US5948570A (en) * | 1995-05-26 | 1999-09-07 | Lucent Technologies Inc. | Process for dry lithographic etching |
US6090717A (en) * | 1996-03-26 | 2000-07-18 | Lam Research Corporation | High density plasma etching of metallization layer using chlorine and nitrogen |
US5849641A (en) * | 1997-03-19 | 1998-12-15 | Lam Research Corporation | Methods and apparatus for etching a conductive layer to improve yield |
US20040152302A1 (en) * | 2003-02-01 | 2004-08-05 | Newport Fab, Llc Dba Jazz Semiconductor | Method for patterning densely packed metal segments in a semiconductor die and related structure |
US6919272B2 (en) * | 2003-02-01 | 2005-07-19 | Newport Fab, Llc | Method for patterning densely packed metal segments in a semiconductor die and related structure |
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